When Lisa starts hallucinating after she drinks the green water on the ride, she sees an image of Selma that resembles the artwork of Ralph Steadman, who's work was often associated with psychedelia.
When Great Aunt Gladys shows off her collection of potato chips, the scene was inspired by Myrtle Young, who appeared on The Tonight Show Starring Johnny Carson (1962). During an interview with David Letterman, Young said she was working in quality control at a potato chip factory, and collected potato chips that looked like, amongst other things, famous people. The scene where Homer ate a chip is a reference to the Johnny Carson appearance, where, whilst Young was looking away, Johnny ate a chip from a separate bowl (not of the collection), Young, thinking Johnny had eaten a chip from her collection, was shocked, before Johnny cleared up the misunderstanding.
Running joke: The interstate diner waitress, the fine-restaurant waitress, and the sperm bank receptionist are all the same female character, right down to the voice and uniform.
Jub-Jub made his debut appearance in this episode; the name of the iguana Jub-Jub came from Conan O'Brien.
Selma singing "(You Make Me Feel Like) A Natural Woman" to Jubjub was a nod to a then-recent Murphy Brown episode in which the title character sings this song to her newborn baby. On the DVD commentary, the Simpsons writers admit that they thought this was an immortal TV moment that people would remember for decades, but now people watch the ending and don't understand why Selma is singing to her iguana.